Holder for extra-long carbon brushes



May 12, 1964 H. R. HARRIS HOLDER FOR EXTRA-LONG CARBON BRUSHES 3Sheets-Sheet 1 Filed Feb. 13, 1961 y 2, 1964 H- R. HARRIS 3,133,218

HOLDER FOR EXTRA-LONG CARBON BRUSHES Filed Feb. 13, 1961 5 Sheets-Sheet2 BY M May 12, 1964 H. R. HARRIS 3, 33,218

HOLDER FOR EXTRA-LONG CARBON BRUSHES Filed Feb. 13, 1961 3 Sheets-Sheet3 wa I IN VEN TOR. flaw/v19 A? flaw/a United States Patent Oilice3,133,218 Patented May 12, 1964 3,133,218 HOLDER FOR EXTRA-LONG CARBONBRUSHES Herman Ray Harris, Grosse Pointe Woods, Mich, assignor, by mesneassignments, to Herman R.

Iarris, Grosse llointe Woods, Mich.

Filed Feb. 13, 1961, Ser. No. 88,930

i 1 Claim. (61. 310-246) The invention refers to brush holders andrelates more specifically to improved means for holding and applyingregulated pressure to extra long conductive brushes dur ing the entirelife thereof while the brushes are in use.

In the past brushes used in conjunction with collector rings, excitersand similar electric apparatus in conjunction with power generation andtransfer have been relatively short so that they are completely used upin a period shorter than that required between maintenance andinspection shut-down of apparatus, such as boilers, with which they areassociated. The periods between shutdowns of the apparatus has in thepast therefore been determined by the life of the brushes. Sinceshutting down of the apparatus with which the brushes are associated isa relatively expensive procedure and may damage apparatus such asboilers, it is desirable to use brushes which have at least as long auseful life as the normal maintenance and inspection period determinedby the apparatus with which they are associated.

The brushes to function elficiently must, however, have a substantiallyconstant pressure exerted thereon. In the past it has been foundextremely difficult to exert such constant pressure on brushes ofsuficient length to have a useful life equal to the maintenance time ofthe other apparatus with which the brushes are associated. Where devicescapable of applying the required constant pressure to extra long brusheshave been provided they have been relatively complicated whereby theexpense and reliability thereof have prevented their generaluse.

It is therefore one of the purposes of the present invention toprovidean improved brush holder for extra long brushes whereby substantiallyconstant pressure may be applied to the brush during the entire usefullife thereof. Another object is to provide a brush holder for extra longconductive brushes including improved automatic means for exertingsubstantially constant pressure on the brushes for theentire useful lifethereof.

Another object is to provide a brush holder for extra long conductivebrushes including a holder box for guiding a brush during use thereofincluding means for attachment to the apparatus with which the brush isused, a spring holder releasably secured to the holder box and aconstant pressure spring secured to the spring holder forexerting aconstant pressure on a conductive brush passing through the holder box.I

Another object is to provide a brush holder as set forth above andfurther including a guard member secured to the holder box andsurrounding the spring and spring holder which guard permits ventilationand visual inspec tion of the position of the brush. p Another object isto provide a brush hold-er as set forth above wherein the spring ispositioned at right angles to the spring holder whereby the spring isbetter positioned to exert a constant pressure on a brush used withexisting holder boxes as the brush is worn away.

Another object is to provide a brush holder for extra long conductivebrushes comprising a holder box for guiding a brush passed therethroughtoward the apparatus with which it is associated, means for mounting aspring on the holder box for exerting regulated pressure on the brush,and means for periodically adjusting the regulated pressure applied tothe brush Whilethe apparatus associated with the brush is in operation.

Another object is to provide a brush holder as set forth above includingmeans for visually indicating the regulated pressure applied to thebrush.

Another object is to provide a brush holder as set forth above whereinthe means for adjusting the regulated pressureapplied to the brush maybe manually actuated with one hand.

Another object is to provide a brush holder as set forth above includingmeans for pivoting the spring for applying pressure to the brush out ofits operating position to permit easy installation of a new extra longbrush in the holder box.

Another object is to provide a brush holder for extra long conductivebrushes comprising a holder box for guiding a brush into engagement withelectrical apparatus associated therewith, a post secured to the holderbox, a carriage guided on and movable longitudinally of the post axiallyof a brush passed through the holder, resilient means for engaging thetop of the brush secured to the carriage, and a substantially constantpressure spring mounted on the carriage and secured to the post forexerting a constant pressure through the carriage on the brush.

Another object is to provide a brush holder as set forth above wherein asignle post, carriage and constant pressure spring is utilized toproduce substantially constant pressure automatically on a pair ofbrushes.

Another object is to provide a brush holder as set forth above whereinthe carriage includes means for initially adjusting the constant springpressure.

Another object is to provide a brush holder as set forth above which issimple in construction, economical to manufacture and eiiicient in use.

Other objects and features of the invention will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawings, illustrating preferred embodiments of theinvention, wherein:

FIGURE 1 is an elevation View of a brush holder for extra longconductive brushes constructed in accordance with the invention.

FIGURE 2 is a view of the brush holder shown in FIGURE 1 taken on theline 2-2 in FIGURE 1. 1

FIGURE 3 is a cross section of the brush holder shown in FIGURE 1 takenon the line 33 in FIGURE 1.

FIGURE 4 is a partly broken away elevation view of a modification of thebrush holder shown in FIGURE 1.

FIGURE 5 is a partially broken away elevation view of the brush holdershown in FIGURE 4 taken in the direction of arrow 5 in FIGURE 4.

FIGUREG is an elevation view of a further modification of the automaticbrush holder shownin FIGURE 1.

FIGURE 6A is an elevation view of still another modification of thebrush holder of FIGURE 1. FIGURE 7 is an elevation View of a manuallyadjustable holder for extra long conductive brushes constructed inaccordance with the. invention. I

FIGURE 8 is an elevation View of the brush holder shown in'FIGURE 7taken in thedirection of arrow 8 inFIGURE7.'

FIGURE 9 is a cross section of the brush holder shown in FIGURE 7 takenon the line 99 in FIGURE 7. 1

FIGURE 10 is an elevation view of a modification of the brush holderillustrated in FIGURE 7; i

FIGURE 11 is an elevation view of another automatically adjustable brushholder for extra long conductive brushes constructed in accordance withthe invention.

FIGURE 12 is an elevation view of the brush holder illustrated in FIGURE'll'taken in the direction of arrow 12 in FIGURE 11. t

FIGURE 13 is a top view of the brush holder illustrated in FIGURES 11and 12.

FIGURE 14 is an elevation view of a modification of the brush holderillustrated in FIGURES lll3.

With particular reference to the figures an embodiment of the presentinvention will now be disclosed.

The brush holder of FIGURES 13 comprises a holder box In, spring holder12 and constant pressure spring 14. In operation the holder box It? issecured to electric apparatus, such as a generator (not shown) with theextra long conductive brush16 passed therethrough to make contact withthe collector rings, exciter commutator or similar part (not shown) ofthe electric apparatus. A constant pressure is exerted on the brushduring the entire useful life thereof by means of spring 14 so that theelectric contact resistance provided through electric conductor 18 doesnot vary due to wear of the brush 16 in use.

More specifically the holder box It) which may be shaped substantiallyas shown in FIGURES 13 includes the passage 20 therethrough throughwhich the brush 16 is passed for guided movement toward the electricapparatus (not shown) from which it is desired to conduct an electriccurrent with the brush 16. The holder box It) is further provided withan elongated opening 22 through which a bolt may be passed to adjustablysecure the holder box to rigid mounting means, such as the electricapparatus with which the brush holder is associated. A button rivet 24is secured to the holder box It) by convenient means such as silversolder so that the head 26 thereof is in spaced relation to the surface28 of the holder box.

The U-shaped spring holder 12 is provided with an elongated slot 36 inend 32 thereof through which the head 26 of the button rivet 24 extendsto removably secure the end 32 of the spring holder 12 to the holder box10. The other end 34 ot the spring holder 12 is secured to the holderbox by means of the removable wing nut 36 threaded on the stud 38carried by the holder box 10.

The spring 14 is secured to the end 34 of spring holder 12 by convenientmeans such as rivets 40. The spring 14 may be of steel or other suitablematerial and is of the constant pressure type. That is to say thatspring 14 exerts a constant pressure on the holder 42 which is securedto the brush 16 by convenient means, such as the rivet 44. Such springsare known per se and will not therefore be considered in detail herein.Conductor 19 is secured to rivet 44 and serves to transfer electricenergy from the brush 16 which may be the usual carbon brush or whichmay be constructed of other suitable electrical conductive material suchas graphite or copper.

In operation of the brush holder shown in FIGURES 1-3 it will be assumedthat a new extra long brush, for example one six inches long isinstalled in the brush holder of the invention. During usage of theelectric apparatus with which the brush holder is associated the brush16 will be gradually worn away as is well known. As the brush 16 is wornaway the constant pressure spring 14 coils automatically and approachesthe opening through the holder box 10. Due to the nature of the constantpressure spring 14 a force of the same magnitude is applied axially ofthe brush 16 until the brush is sub-j stantially entirely worn away bythe electric apparatus associated with the brush holder.

Thus it can be seen that through the provision of an extremely simplebrush holding device an extra long brush may be used in conjunction withelectric apparatus from which it is desired to conduct electric energywhich brush need not be changed between maintenance of the electricapparatus with which it is associated and which brush conducts aconstant electric current from the electric apparatus due to theconstant pressure applied to the brush regardless of the length thereofautomatically by the spring 14. I

A modification of the brush holder shown in FIGURE 1 is illustrated inFIGURES 4 and 5. The brush holder illustrated'in FIGURES 4 and 5comprises a holder box 46 similar to the holder box Ill and having thespring holder 48 and ventilated guard 50 secured thereto. The springholder 48 includes the L-shaped bracket 52 secured thereto and extendingtransversely thereof as shown.

The constant pressure spring 54 similar in all respects to the constantpressure spring 14 is secured to the bracket 52 by convenient means,such as rivet 56 so that the spring holder 43 and spring 54 arepositioned at right angles to their position in the brush holderillustrated in FIGURES 1-3. Such positioning of the spring 54 hasdistinct advantages when the constant pressure spring 54 is used inconjunction with standard box holders 46 in that with such positioningthe spring 54 provides a constant pressure on the brush 58 withoutinterference therewith of the box holder 46 when the brush is worn away.Guard is provided to protect the spring 54 from contact with objectswhich might destroy the constant pressure exerted thereby.

Another modification of the extra long brush shown in FIGURE 1 isillustrated in FIGURE 6. The brush holder illustrated in FIGURE 6includes the holder box 65? having the opening 62 therethrough throughwhich the brush 64 is guided as before. The constant pressure spring 66is secured to the holder box 60 by convenient means 68 so that thespring 66 exerts a constant axial pressure on the brush 64 during usethereof as the brush 64 is worn away by the electric apparatus withwhich it is associated.

The ventilated guard and spring guide 70 which extends around threesides of the carbon brush 64 is pivotally secured to the holder box 60at 72. A slot 74 is provided in the upper portion 75 of guard 70. Theperiphery of the slot 74 may be clamped between the lock nut 76 onthreaded stud 77 and the flange 79 of holder box 66 to lock the guard 76in the position shown in FIGURE 6.

The spring guide and guard 70 is further provided with an elongated slot78 therein through which the length of the brush 64 may be observed.When it is desired to change the brush 64 the lock nut 76 is loosened,the guard 70 is pivoted about pivot 72 to provide access to the constantpressure spring 66 which may be held in an uncoiled extended positionwhile a new brush 64 is placed in the passage 62.

FIGURE 6-A illustrates a brush holder including many of the moredesirable features of the brush holders of FIGURES 1 and 6. The brushholder of FIGURE 6-A comprises the holder box 61 similar to holder box60 and an L-shaped spring holder and spring guide 69 similar to springholder and guide 12. Spring holder and guide 69 is secured to the holderbox 61 at the top by lock nut 71 and at the bottom by wing nut 73similar to lock nut 76 and wing nut 36. Operation of the brush holder ofFIG- URE 6-A is similar to the operation of the brush holder ofFIGURE 1. V

The brush holder shown in FIGURE 7 comprises a holder box 80 for guidingthe extra long brush 82 toward electric apparatus with which the brushholder is associated. Fulcrum plate means 84 for applying a regulatedpressure to the brush 82 and adjusting and locking means 86 for manuallyadjusting the regulated pressure applied to the brush 82 and locking theadjusting mechanism in adjusted position are also provided in the brushholder illustrated in FIGURE 7.

The holder box 80 is provided with the passage 88 therethrough throughwhich the brush 82 extends axially. An elongated slot 96 is provided inthe holder box 80 to permit adjustably securing the holder box to theelectric apparatus with which it is associated by convenient means (notshown). Holder box 80 further includes the brackets 92 and 94. Bracket92 rotatably receives the end 96 of adjusting screw 98 therein. Bracket94 is provided with a passage 100 therethrough in which the adjustingscrew 98 is also rotatably received.

The fulcrum plate means 84 for applying a regulated pressure to thebrush 82 comprises the compression spring 102 secured to the U-shapedbracket 104 at one end and to the abutment 106 at the other. TheU-shaped bracket 104 as shown is secured to the fiange 108 of thepivotally mounted bracket 110. Bracket 110 is secured to a carrier 112by pivot pin 114 and locked in a fixed position by means of cotter pin116. Thus with the carrier 112 positioned along adjusting screw 98 asdesired any pre determined pressure within the pressure range of thespring 102 may be exerted on the brush 82.

The shaft 118 which extends vertically from the abutment 106 through theU-shaped bracket 104 and flange 108 is provided with annular ridges 120thereon which indicate the compression in the spring 102. Each visibleridge may represent a particular spring pressure, such as one pound.Thus, if two ridges are visible the spring in its compressed conditionwould indicate two pounds of pressure being applied to the brush 82. Thepressure exerted on the brush 82 may therefore be kept within requiredlimits by periodic observation of the ridges 120 and resetting of theposition of the carriage 112 as the brush is Worn away. A tubular shaftguide 121 flared at each end and pressed into an opening 123 throughbrackets 104 and 110 is provided to prevent the ridges 120 from catchingon the opening 123 and to insure axial movement of the shaft 118.

The adjusting and locking means 86 for adjusting the regulated pressureapplied to the brush 82 by the spring 102 comprises the adjusting screw98 rotatably supported by the holder box 88, the carriage 112 havingfeed nut 122 fixedly secured thereto, collar 124 rigidly secured to theadjusting screw 98 for rotation therewith, locking wing nut 126 andadjusting handle 128.

In adjusting the position of the carriage 112 to adjust the regulatedpressure applied to the brush 82 by the spring 102 the wing nut 86 isfirst loosened. The adjusting screw 98 is then rotated within thebrackets 92 and 94 to cause the feed out 122 to travel along theadjusting screw 98 whereby the carriage 112 is positioned axially of theadjusting screw 98. The wing nut 126 is then again tightened to lock theadjusting screw in position. It will be noted that the entire adjustmentmay be accomplished with one hand so that a safety feature is providedwhen the pressure exerted on the brush 82 is adjusted while the electricapparatus with which the brush is associated is operating.

When it is desired to replace the brush 82 the pin 116 is removed fromthe bracket 110 so that the bracket 118, flange 188 and spring 102 maybe pivoted about pivot pin 114 to provide room for easy insertionof anew extra long brush 82 into the passage 88. The member 118 carrying theflange 108 and spring 102 is then pivoted back into the position shownand the cotter pin 116 is again secured through the aligned opening inthe carrier 112 and bracket 110 as shown in FIGURES 7 and 8.

A modification of the manually adjustable holder for extra long rods, asshown in FIGURES 79, is illustrated in FIGURE 10. The modified brushholder illustrated in FIGURE includes adjusting and locking means 130similar to that of the brush holder of FIGURES 7 9 which will thereforenot be considered in detail. Similarly the holder box 132 of the boxholder shown in FIGURE ,10 will not be described in detail except toindicate that a track 134 is provided on both sides of the upwardlyextending portion 136 thereof along which the carriage 140 is guided bymeans of flanges 142 during adjustment of the adjusting screw 144.

The means 146 for applying a regulated pressure to the brush 148 of thebrush holder illustrated in FIGURE 10 has the advantage of being simplerin construction than that provided in FIGURES 7-9 but cannot be pivotedout of the way during replacement of the brush 148 as with the means 84of the brush holder shown in FIG- URES 7-9.

The brush holder for extra long carbon brushes illus- 6 trated in FIGURE11 also includes a holder box 150 having a passage 152 therethroughadapted to receive the brush 154 for axial movement toward an electricapparatus (not shown) as before, a carriage 156 for supporting constantpressure means 158 operable to exert a constant axial pressure on thebrush 154 and post 160 along which carriage 156 travels as the brush 154is worn away.

Holder box 150 may be secured to the electric apparatus with which thebrush holder is associated by convenient means (not shown). Post 168 issecured to the holder box 151) by convenient means such as the flange162 and bolts 164.

Carriage 156 comprises side plates 166 and 168 spaced from each other bysleeves 170 extending therebetween and assembled therewith by means ofscrews 172.- Two sleeves 170 are provided in vertically spaced relationon one side of the post 168 and a sleeve and roller 161 are provided invertically spaced relation on the other side of post 160, as shown bestin FIGURE 11, whereby only vertical movement of the carriage 156 withrespect to the post 161) is possible. Roller 161 also serves to guidespring 158.

A further rotatable shaft 174 is provided between the plates 166 and 168having an axially extending slot 176 therein through which the end 178of the constant pressure spring 158 is inserted. The other end of theconstant pressure spring 158 is secured to the post 160 in the positionshown by convenient means such as the screw 180. Thus in operation, asthe brush 154 is worn away the carriage 156 is caused to move toward theholder box 1541 as the constant pressure spring 158 coils about theshaft 174 to exert a constant pressure on the brush 154.

The shaft 174 is further provided with radially enlarged portions 182 atthe ends thereof having radial recesses therein into which pegs 184 maybe inserted to initially adjust the tension of the spring 158 so thateach spring in a multiple installation will provide the same pressure onthe brushes 154 in the installation regardless of manufacturingimperfections in the springs and/ or slight permanent set of thesprings.

The force exerted by the spring is transferred from the carriage 156 tothe brush 154 by means of the screw 184.

FIGURE 14 illustrates a modification of the brush holder shown inFIGURES 11-13 wherein a pair of brushes 185 and 188 are provided withregulated pressure axially thereof by means of a brush holder, as shownin FIG- URES 1113, wherein the force is transferred from the carriage198 to the brushes 186 and 188 by the bolt 192 having the U-shapedbracket 194 sleeved thereon and urged axially outwardly thereof by meansof the spring 196. The bracket 194 is loosely sleeved on the bolt 192whereby slight tilting of the bracket 194 is possible in operation sothat pressure on the brushes 186 and 188 will automatically bemaintained equal.

While both automatically and manually adjustable brush holdersconstructed in accordance with the invention have been specificallydisclosed together with particular modifications thereof it will beunderstood that many other modifications of the brush holder of theinvention will readily suggest themselves to those skilled in the art.It is therefore the intention to include all such modifications withinthe scope of the invention.

The drawings and the foregoing specification constitute a description ofthe improved holder for extra long carbon brushes in such full, clear,concise and exact terms as to enable any person skilled in the art topractice the invention, the scope of which is indicated by the appendedclaim.

What I claim as my invention is:

A holder for an extra long carbon brush for use in maintainingcontrolled contact between the brush and electric apparatus with whichthe brush is used, comprising a substantially L-shaped holder boxincluding a first portion having an opening therethrough adapted toreceive a brush and guide the brush toward the electric apparatus and asecond portion substantially perpendicular to the first portion having aflange thereon with a threaded opening therein extending substantiallyparallel to the first portion and in the same direction, an L shapedspring holder having openings through both ends thereof, a boltextending through the opening in one end of said spring holderthreadedly engaging the opening in the flange of said second portion ofsaid holder box for securing said one end of said spring holder to saidholder box, a threaded stud secured to the first portion of said holderbox extending through the opening in the other end of said springholder, a nut threadedly engaging said threaded stud for releasablysecuring the other end of said spring holder to said holder box and aconstant pressure spring secured to said 8 spring holder adjacent saidother end thereof for exerting a constant pressure on a brush guided bythe holder box as the brush is worn away in use.

References Cited in the file of this patent UNITED STATES PATENTS1,994,502 Burnite Mar. 19, 1935 2,602,100 McDonald July 1, 19522,629,061 Swarthout Feb. 17, 1953 2,695,968 Welch et al. NOV. 30, 19542,769,107 Potter Oct. 30, 1956 2,836,745 Gillie May 27, 1958

